Hot-air feed for furnaces.



w. B. COLEGROVE. HOT AIR FEED FOR FURNACES.. APPLlCATlOR FILED AUG-B.1917.

1 w Patented Jan. 29," 1918.

Elma/WM Williamfi. UaZe mz/e bit am i,

WILLIAM B. COLEGROVE, OF DETROIT, MICHIGAN.

HOT-AIR FEED ron summons.

To all whom it may concern."

Be it known that l, WiLLiAM B. COLE- ouovn', a citizen of the UnitedStates, residing at Detroit, in the county of Wayne and State ofMichigan, have invented a new and useful Hot-Air Feed for Furnaces, ofwhichthe followin is a specification.

This invention relhtes to furnaces or heaters, and has for its principalobject the provision of simple and efficient means for feeding intothecombustion space above the fire pot a flow of warm air to intermixwith and assist the combustion of the gases arising from the fuel,provision being made for preheating the air delivered into thecombustion chamber by introducing it through a drum surrounding thesmoke pipe, and, which communicates with a passage leading through saidpipe in the path of travel of the hot gases of combustion escapingtherethrorgh, whereby the temperature of the air in its passage into thecombustion cham-, her is raised sufficiently to prevent the'chilling ofthe gases liberated from the fuel and insure a more complete combustionthereof. The above object is attained by the employment of theconstruction illustrated in the accompanying drawings, in which,

Figure 1 is a central vertical. sectional view of a warm air furnace,showing the present invention consisting of a heating drum embracing asection of the smoke pipe through which a hot air feed pipe communicateswith the drum and with the combustion chamber of the firepot.

Fig. 2 is a central longitudinal section through the drum detached fromthe furnace, showing the warm air feed pipe, a section of the smoke pipeand air damper assembled therein.

Fig. 3 is a transverse section through the drum and interior partsshowing the damper controlled air inlet ports.

Referring to the parts illustrated'in the drawings by the characters ofreference marked thereon, 1 designates an ordinary hot air furnacehaving the usual fire pot '2 and combustion chamber 3 from which the hotgases of combustion escape through passages 4 and flue 5 to the smokestack (5 of the furnace, as is common.

The present invention, which constitutes an attachment adapted to beinterposed between the furnace and the smoke stack, consists of acylindrical heating drum 7 closed at its ends by heads 8, one of whichis pro- V the drum.

Specification of Letters Patent. Patentgfll J 2gp 19y Application filed.August a, 1917. Serial No. 185,024.

vided with a circular series of apertures 9 for the admission of air tothe interior of A circular damper plate 10, having a series of apertures11 registerable with the apertures 9, is movably mounted upon studs orrivets 12 extended throu 'h arcuate slots 13 therein andanchored in t tohead of the drum, and the periphery'ot' the damper plate is providedwith aprojecting handle let by means of which it may be shifted to varythe areas of the registering apertures and control the passage of aminto the drum.

Spaced concentrically within the drum,

and extending axially throughthe heads8 thereof. is a sleeve or pipesection 15 which is adapted to receive at one end the flange of the flue5 of the furnace, and may be connected at its opposite end in anysuitable manner to the smoke stack 6. preferably by means of the usualT-shaped fitting 16 hav-f ing a check draft damper 17, asshown inFig. 1. This pipe 15, which forms a section of the smoke pipe throughwhich the burned gases escape from the furnace, has mounted therein awarm air flue 18, one

end of which communicates with the interior of the drum 7 throughanelongated aperture 19 formed in the upper wall of the pipe 15, and theopposite end of said llue extends through the inner end of said pipeand'receives one end of a feed pipe 20 which extends into the combustionchamber 3 of the furnace and terminates centrally therein above the firepot 2 in a downwardly turned outwardly flared discharge nozzle '21.

It will now be understood that the draft, created through the combustionchamber by the escaping products of combustion through the smoke pipewill cause a current of air to be drawn through the air inlet apertures9 into the heating drum where it will become heated by contact with thepipe 15 through which the burning gases escape to the smoke stack, andfrom the drum the heated air will be drawn through the flue 18 and feedpipe 20 from which it will discharge at the nozzle 21 into thecombustion chamber directly over the center of the mass of burning fuel.in the fire pot, as indicated by arrows in Fig. 1. The air thusintroduced into the combustion chamber will intermiz; with the gasesliberated from the fuel and form a combustible mixture which will assistin the burning of the gases within the combustion chamber beforeescaping into the smoke stack. Owing to the fact that the air drawn inthrough the drum is-subjected to the intense heat of the embracedsection of the smoke pi e around which it circulates, said air willbecome heated to a'comparatively "high tem-perature and consequentlyexpanded, and because of the greater density and pressure of theexterior air will be caused to discha ge Wi h c n dera l ce t o ghhenozzll f t ep eed p pe in a m nn t supply ablast of heated air atsuchtemper.-

atureas not to materially cool the gases in the combustion chamber, thusinsuring a morenearly perfect commingling of the air and gasesbecause oftheir relatively uniform temperatures, whereby the combustion of the gas'es is greatly facilitated and a more completec nsumption of thecalorific "'11 filaim; a

1. The combination with a combustion properties chamber havinga smokepipe communicatray through he wal of sa d sm e ing therewith, of an airheating drum surround ng sa d p pe and havmg an air nlet openingtherein, and a hot air feed piper natihg in a d ic i a ge o zle wit Said.m iis l on ch mber- 2. The combination with a combustion chamber havinga smoke pipe communicat- 7 ing therewith, of an air heating drumconcentrically embracing said pipe and having damper controlled airinlet openings in one end thereof, a hot air flue within said smoke pipeand communicating with said drum through a lateral opening in the wallof said pipe, said flue extendingat one end through the inlet end ofsaid smoke pipe, and a feed pipe extending from said flue andterminating in a downwardly turned discharge nozzle centrally withinsaid combustion chamber.

3. A hot air feed for a combustion chamber comprising a section of smokepipe adapted for connection with said chamber,

an air heating drum closed at its ends and receiving axiallytherethrough said smoke pipe, said drum having a circular series ofdamper controlled air inlet ports in one end thereof, a hot air fluearranged longitudinally within said smoke pipe and in communicationlaterally through the wall thereof with the interior of said drum andhaving its outlet end within the inlet end of said smoke pipe, and afeed pipe extension for said fine having a nozzle adapted to dischargeinto said combustion chamber.

In testimony whereof I sign this specification.

WILLIAM B. COLEGROVE.

Qoples toll thiEiPQ-tent maybe 'obt ainedyfor five cents each, byaddressing the Commissioner of Patents,

' i Washington,i).0."

